1. Field of the Invention
This invention relates to a process for producing androstane steroids. More particularly it relates to an improvement in the culture medium used in the fermentative production of androstane steroids.
2. Description of the Prior Art
It is well known in the art that an androstane steroid can be produced by microbiological conversion of a sterol with a microorganism belonging to the genus Mycobacterium (hereinafter abbreviated as "M."). However, this method involves some disadvantages in that the yield of the desired steroid is not yet satisfactory with the rate of production being low.
It is also known that in the steroid fermentation wherein progesterone is hydroxylated at the 11.alpha.-position with the aid of Rhizopus nigricans one of fungi, the substrate (i.e., progesterone) can be fed at a higher concentration by adding it as a mixture with raw egg yolk in the course of incubation, as compared with the cases where progesterone is added as a solution in acetone without use of raw egg yolk (Japanese Patent Publication No. 9765/1957).